<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div class="outer" id="outer">
        <ul class="list list-1">
            <li name="li-item" class="item item2 item3">list-one</li>
            <li class="item">list-two</li>
            <li class="item">list-three</li>
        </ul>
    </div>
    <div class="outer2" id="outer"></div>
    <ccc name="ccc">ccc</ccc>

    <script>
        var log = console.log;

        var outerEl = document.getElementById("outer");
        // Element也有此方法
        var items2 = outerEl.getElementsByTagName("li");
        // 查询能被解析的节点
        var items3 = document.getElementsByTagName("ccc")

        // 功效等同于 document.all
        console.log(document.getElementsByTagName("*").length === document.all.length)

    </script>
</body>

</html>